where \(i\)  labels different components of energy density content. We also assumed that, for each component, the relation between energy density and pressure is given
by: \(p_i = w_i\rho _i\) . The index '0' denotes unknown value of the density component \(\rho _{0,i}\)  at the epoch when \(a=1\)In standard cosmology (\(\alpha =0\) ), after normalization of the scale factor \(a\in (0, 1]\) , this is a present day epoch. Thus, in cosmological applications, initial data are replaced by a present day data.. This solution depends on time implicitly only throughout the dynamical variables \((a,\Phi )\) . Due to the coupling \(\alpha (\Phi )\) , it is possible to relate effective mass of the scalar field to the density of matter, so that its range is influenced by local environment. Such a process, called 'Chameleon mechanism', is responsible for hiding the effects of a massive scalar field on scales smaller than the Solar System, where it should be possible to detect its presence [1]}.
